Dr. Michael F. Brown
Departments of Chemistry and Physics
University of Arizona
Tucson, Arizona

Monday, April 20, 2009
3:00 pm (CT)
3269 Beckman Institute

Abstract

Rhodopsin is a prototype for G protein-coupled receptors (GPCRs) that are targets of the majority of pharmaceuticals in use today. The visual system involving rhodopsin is the sine qua non of receptor biology and signal transduction. Moreover, vision involves one of the fastest photochemical processes in nature with fundamentally interesting quantum chemistry. A multi-disciplinary combination of solid-state 2H NMR together with molecular dynamics simulations and electronic spectroscopy indicates how the retinal ligand, the protein rhodopsin, and the lipid bilayer interact. We describe how conformational strain of retinal is implicated in visual excitation. Retinal is coupled to the protein conformation which in turn depends on the lipid bilayer -- a concept we call frustration. Last, the role of polyunsaturated lipids is explained by a new flexible surface model in terms of coupling of the protein and the bilayer due to elastic curvature forces.